RD was responsible for the ascertainment of the patients from France, was involved in the coordination of the study and drafted the manuscript. DMD was involved in the molecular genetic studies and data analysis and helped to write the manuscript. AG carried out the MLPA experiments and participated in the analysis. WM, RM, HJG, SR, PF and MW recruited the German subjects. PC was involved in the evaluation of the French patients. MCM, ML and MW supervised the clinical evaluation of patients. CB conceived the study and coordinated it, supervised the molecular studies and was responsible for writing the manuscript. All authors read and approved the final manuscript.
